One view is that the robot kicked up the object during its wheeling around the area. Another thought is that it was tossed there by a nearby impact event. Maybe it’s a windblown rock…or is it an ugly looking Mars turtle?

Now James Rice, science team member of the Mars Exploration Rover Project and senior scientist at the Planetary Science Institute, has piped in on the mystery.

“By now you must have heard about the very unusual rock (Pinnacle Island) which just appeared before us at Cook Haven. There were many articles out with images showing a before and after from Sols 3528 and 3540 (12 sols),” Rice says.

“However, my new analysis shows that the appearance of Pinnacle Island can be further refined to have occurred between Sols 3536 and 3540 (only 4 sols),” Rice told this reporter.

Rice said that most likely the rover did it on Sol 3540 when it did a turn-in-place and bump. “We popped it out. But we are still trying to figure this out along with where it originally was located (I have a candidate divot) and then the bigger question: what is this rock?”

Pinnacle Island has a very unusual composition, Rice said, like nothing the MER scientists have ever seen before.